1. Field of the Invention
This invention relates to a new and improved blow molded neck construction for a bottle or other container, a cap therefor, a method of forming said neck and molds for forming said neck. More particularly, it relates to the neck finish for a blow molded plastic bottle characterized by the fact that when used with a cap having a plug (i.e., inner skirt) the surface of the neck against which the plug seals is a seal surface without parting lines and no portion has a diameter less than that of the seal surface. Hence, the plug seals against a smooth surface and leakage is prevented.
2. Description of Related Art
An exemplar of the prior art is U.S. Pat. No. 4,691,834 which shows an upward inward directed flexible flange sealing against the corner of the intersection of the outer wall of the plug and the underside of the top of the cap. The neck sealing surface is, inherently, somewhat uneven and ragged since the neck is cut or sheared adjacent this sealing surface. In the present invention, however, the neck is trimmed on the edge above the seal surface but such edge is not the portion of the neck which seals against the cap plug.
The references cited against said U.S. Pat. No. 4,691,834 are likewise distinguishable.
U.S. Pat. Nos. 4,625,876 and 4,798,301 show curved plug contacting surfaces but these are of substantially the same diameters as the inner edge of the flanges which engage the underside of the top of the cap.